Annual report pursuant to Section 13 and 15(d)

Stock Based Compensation (Stock Options Outstanding) (Details)

v2.4.0.6
Stock Based Compensation (Stock Options Outstanding) (Details) (USD $)
12 Months Ended
Dec. 31, 2011
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Outstanding, Options 364,268
Outstanding, Weighted average exercise price $ 42.76
Exercisable, Options 220,293
Exercisable, Weighted average exercise price $ 44.25
Intrinsic value of outstanding stock options at December 31, 2011 $ 889,941
Intrinsic value of exercisable stock options at December 31, 2011 $ 463,431
$20.28 - 29.99 [Member]
 
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, minimum $ 20.280
Exercise Price Range, maximum $ 29.99
Outstanding, Options 28,500
Outstanding, Weighted average exercise price $ 23.24
Exercisable, Options 13,500
Exercisable, Weighted average exercise price $ 23.29
$30.00 - 39.99 [Member]
 
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, minimum $ 30.00
Exercise Price Range, maximum $ 39.99
Outstanding, Options 40,100
Outstanding, Weighted average exercise price $ 35.48
Exercisable, Options 26,600
Exercisable, Weighted average exercise price $ 35.71
$40.00 - 57.79 [Member]
 
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, minimum $ 40.00
Exercise Price Range, maximum $ 57.79
Outstanding, Options 295,668
Outstanding, Weighted average exercise price $ 45.63
Exercisable, Options 180,193
Exercisable, Weighted average exercise price $ 47.09